JP2012519887A - Backlight recirculation in transflective liquid crystal displays. - Google Patents

Abstract

  Techniques are provided for recycling light from the backlight unit that would otherwise be blocked by the reflective portion of the pixel in the transflective LCD. The light is redirected into the transmissive part of the pixel, thus increasing the light efficiency and brightness of the pixel. The technique can be used in transflective LCDs that transmit light in a circular or linear polarization state.

Description

  The present disclosure relates to a liquid crystal display (LCD).

  The approaches described in this section are approaches that can be explored, but not necessarily approaches that have been previously conceived or explored. Thus, unless otherwise indicated, none of the approaches described in this section should be considered as prior art simply by including them in this section.

  Transflective LCDs may be used in cell phones, electronic books, and personal computers, in part because the readability of transflective LCDs is usually not limited by ambient light conditions. A transflective LCD comprises an array of pixels each having a reflective portion and a transmissive portion. In the reflective part of the transflective LCD pixel, there may be a metal reflector covering the thin film transistor unit. In a transflective LCD that uses a relatively small metal reflector in the pixel, sufficient backlight may be able to transmit the pixel, but ambient light is not reflected to the extent that the pixel is shown with the desired brightness. There is.

  On the other hand, in a transflective LCD using a relatively large metal reflector in a pixel, sufficient ambient light may be reflected, but sufficient backlight cannot transmit the pixel. For example, a circularly polarized backlight may be blocked by a relatively large metal reflector in the reflector and cannot be efficiently redirected to the transmissive part. This significantly reduces the light output efficiency of the backlight unit (BLU) and reduces the overall light transmittance and brightness of the pixels of the transflective LCD. The problem is particularly acute when the area of the reflective part is comparable to or larger than the area of the transmissive part in the pixel.

  A technique for recycling the backlight in a transflective LCD is described. Various modifications to the preferred embodiment and the general principles and features described herein will be readily apparent to those skilled in the art. As such, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features described herein.

1. General Overview In some embodiments, a first metal reflective layer is adjacent to the inner surface of the bottom substrate within the reflective portion of the transflective LCD unit structure to efficiently recycle the backlight. As used herein, “an inner surface of a bottom substrate” refers to a bottom substrate facing a liquid crystal material within a transflective LCD unit structure, as further described. Refers to the surface. The term “transflective LCD unit structure” may refer to a pixel or sub-pixel within a transflective LCD.

  The reflective region may be located between the first metal reflective layer and the backlight. The reflective region may comprise a scattering or diffractive type overcoating layer. Additionally and / or optionally, the first phase tuning film is formed between the first metal reflective layer and the BLU in the reflector, so that the recirculated light passing through the first phase tuning film The phase and polarity state may be changed.

  In some embodiments, the first metal reflective layer contacts the inner surface of the bottom substrate. In some embodiments, the first metallic reflective layer is present in addition to the second metallic reflective layer located on the top surface of the overcoating layer, near the liquid crystal layer. The second metal reflective layer may be a concavo-convex metal reflector having a bumpy surface structure facing ambient light. Thus, in these configurations, the pixel comprises at least two metal reflective components in the reflector. The second metal reflective layer effectively reflects ambient light, but the first metal reflective layer adjacent to the inner surface of the bottom substrate effectively recycles the backlight received from the BLU. In some embodiments, one or both metallic reflective layers comprises an opaque layer such as aluminum (Al) or silver (Ag).

  In some embodiments, a portion of the backlight may be similarly reflected and recycled by the BLU facing surface of the second metal reflective layer. In these embodiments, the second phase tuning film is also inserted between the second metal reflective layer and the BLU in the reflector and the phase or polarity of the recirculated light passing through the second phase tuning film May change.

  In some embodiments, the transflective LCD described herein transmits linearly polarized light. In these embodiments, the transflective LCD may be configured with one or more linear polarizers.

  In some embodiments, the transflective LCD described herein transmits circularly polarized light. In these embodiments, the transflective LCD may be configured to have one or more circular polarizers comprising a quarter wave plate or a combination of half wave plate and quarter wave plate. Linearly polarized light is reflected by the metallic reflective layer and may be recycled one or more times in the reflective region until it exits through the transmission towards the viewer.

  Circularly polarized light may be reflected by the metallic reflective layer, depolarized into one or other mixed light polarization state and reflected into the reflector. Usually, the reflected light is elliptically polarized. In order to better redirect scattered elliptically polarized light within the transmission, the pixel structure may comprise a light redirecting prism film. The pixel structure may comprise a cholesteric liquid crystal film as a circularly polarized reflector in order to better recirculate the scattered unpolarized or elliptically polarized light within the transmission.

  In embodiments, the light from the BLU is effectively recirculated from the reflector to the transmissive part, increasing the light output of the BLU and further increasing the brightness of the transmissive part.

  The benefits of this approach include transflective LCDs with high backlight output efficiency. Further benefits include transflective LCDs characterized by high brightness and significantly lower power consumption compared to others. These features are valuable for various applications with different modes of operation. For example, the transflective LCDs described herein exhibit color images in transmissive and transflective modes and black and white monochrome images in reflective mode, and have good ambient light readability and low power consumption.

  In some embodiments, the transflective LCD described herein includes, but is not limited to, a laptop computer, netbook computer, cellular radiotelephone, electronic book reader, point-of-sale terminal, desktop computer, computer workstation A computer kiosk, or a computer including a computer coupled or integrated with a gasoline pump, and various other types of terminals and display units.

  In some embodiments, the method includes providing a backlight source for the described transflective LCD and transflective LCD.

  Various modifications to the preferred embodiment and the general principles and features described herein will be readily apparent to those skilled in the art. As such, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features described herein.

  Various embodiments of the present invention are described below with reference to the accompanying drawings provided to illustrate, but not limit, the invention. In the drawings, the same designation indicates the same element.

FIG. 2 shows a schematic cross-sectional view of an exemplary transflective LCD unit structure configured to transmit linearly polarized light with a polarization recycling film. FIG. 4 shows a schematic cross-sectional view of an exemplary transflective LCD unit structure configured to transmit linearly polarized light by means of a polarization recycling film and a light redirecting film. FIG. 4 shows a schematic cross-sectional view of an exemplary transflective LCD unit structure configured to transmit circularly polarized light with a reflective polarizer. FIG. 3 shows a schematic cross-sectional view of an exemplary transflective LCD unit structure configured to transmit circularly polarized light with a reflective polarizer and a light redirecting film.

  The drawings are not rendered according to a fixed scale.

2. Structural Overview 2.1 Linear Polarization FIG. 1 shows a schematic cross-sectional view of an exemplary transflective LCD unit structure 100. The LCD unit structure 100, which may include a pair of linear polarizers to transmit linearly polarized light, has a configuration for recirculating linearly polarized light.

  In some embodiments, the LCD unit structure 100 includes at least a transmissive part 101 and a reflective part 102. The liquid crystal layer 110 is located between the bottom substrate 114 and the top substrate 124. The transmission unit 101 may have a liquid crystal cell gap different from the liquid crystal cell gap of the reflection unit 102. As used in this disclosure, “a liquid crystal cell gap” refers to the thickness of a liquid crystal layer in a transmissive part or a reflective part.

An overcoating layer 113 may be deposited in the reflective portion 102 to create a liquid crystal cell gap in the reflective portion that is smaller than the liquid crystal cell gap in the transmissive portion 101. In some embodiments, due in part to the overcoating layer 113, the liquid crystal cell gap of the reflective portion 102 may be about half of the liquid crystal cell gap of the transmissive portion 101. In various embodiments, the overcoating layer 113 may include an acrylic resin, a polyamide, or a novolac epoxy resin. The overcoating layer 113 may be doped with inorganic particles such as silicon dioxide (SiO ₂ ) to provide scattering and diffractive optical properties.

  The first metal reflective layer 115 may be on the inner surface of the bottom substrate 114 in the reflector 102, which is the top surface of the bottom substrate 114 of FIG. The first metal reflective layer 115 can be prepared as a stretched gate metal or a separate reflective metal layer during the TFT process. The first metallic reflective layer 115 may include an opaque reflective metallic material such as Al or Ag and may occupy all or a portion of the entire area of the reflective area 102. The inner surface, which is the upper surface of FIG. 1, of the overcoating layer 113 may be coated with a second metallic reflective layer 111 such as aluminum (Al) or silver (Ag) to serve as a reflective electrode. In some embodiments, the second metal reflective layer 111 may be an uneven metal layer.

  The bottom substrate 114 may be made of glass. A transparent indium tin oxide (ITO) layer 112 may be provided as a pixel electrode on the inner surface of the bottom base 114 in the transmissive portion 101. A color filter not shown in FIG. 1 may be deposited on or near the surface of the upper substrate 124. The color filter may cover both the transmissive part 101 and the reflective part 102, or may only cover the transmissive part 101. The ITO layer 122 may be positioned as a common electrode between the upper base material 124 and the liquid crystal layer 110. Bottom linear polarizer 116 and top linear polarizer 126 may be mounted on the outer surfaces of bottom substrate 114 and top substrate 124, respectively.

  A polarization recycling film 134 may be located between the BLU 136 and the bottom linear polarizer 116. The polarization recycling film 134 reflects light in one polarization state such as the first transverse polarization state and transmits light in another polarization state such as the second transverse polarization state orthogonal to the first transverse polarization state. A dual brightness enhancement film may be provided. The polarization recycling film 134 may comprise a plurality of layers. In one embodiment, the dual brightness enhancement film may be a Vikuiti ™ DBEF film commercially available from 3M.

  In operation, in the reflector 102, the incident backlight 132a from the BLU 136 first passes through the light recycling film 134 and then enters the bottom linear polarizer 116 to enter the bottom region of the reflector 102 in a particular linear polarization state. to go into. The incident backlight 132 a is incident on the first metal reflective layer 115. Similarly, the incident backlight 132 b may be incident on the bottom surface of the second metal reflective layer 111. Incident backlights 132a and 132b may pass through a bottom linear polarizer 116 that is randomly reflected and has the same polarization state. Reflected by the polarization recycling film 134, the incident light 132a and 132b is recycled and (1) covered with the first metal reflective layer 115 or (2) covered with the first metal reflective layer 115. Although not, it may be redirected into the transmissive part 101 from the region covered with the second metal reflective layer 111.

  In this way, the BLU light portion in the reflection unit 102 is recirculated in the transmission unit 101, and backlight recirculation is realized. Through the backlight recirculation described herein, more light is redirected from the reflective portion 102 into the transmissive portion 101. Therefore, a high light output efficiency from the BLU can be obtained, and an increased luminance in the transmission unit 101 can be achieved. Because more backlight is used more efficiently, power consumption from the BLU can be reduced, resulting in a transflective LCD with efficient power saving capabilities.

2.2 Linear Polarization with Light Redirecting Film FIG. 2 shows a schematic cross-sectional view of an exemplary transflective LCD unit structure 200. The LCD unit structure 200, which may include a pair of linear polarizers to transmit linearly polarized light, has a configuration for recirculating linearly polarized light.

  In some embodiments, the LCD unit structure 200 includes at least a transmissive portion 201 and a reflective portion 202. The liquid crystal layer 210 is located between the bottom base material 214 and the top base material 224. The transmission unit 201 may have a liquid crystal cell gap different from the liquid crystal cell gap of the reflection unit 202.

The overcoating layer 213 may be positioned in the reflective portion 202 to create a liquid crystal cell gap of the reflective portion that is smaller than the liquid crystal cell gap of the transmissive portion 201. In some embodiments, due in part to the overcoating layer 213, the liquid crystal cell gap of the reflective portion 202 may be about half of the liquid crystal cell gap of the transmissive portion 201. The material of the overcoating layer 213 may include an acrylic resin, a polyamide, or a novolac epoxy resin. The overcoating layer 213 may be doped with inorganic particles such as silicon dioxide (SiO ₂ ) to provide scattering and diffractive optical properties.

  The first metal reflective layer 215 may be located on the inner surface of the bottom substrate 214 in the reflector 202, which is the top surface of the bottom substrate 214 of FIG. The first metal reflective layer 215 can be prepared as a stretched gate metal or a separate reflective metal layer during the TFT process. The first metallic reflective layer 215 may comprise an opaque reflective metallic material such as Al or Ag and may occupy all or a portion of the entire area of the reflective area 202. The inner surface, which is the upper surface of FIG. 2, of the overcoating layer 213 may be coated with a second metal reflective layer 211 such as aluminum (Al) or silver (Ag) to serve as a reflective electrode. In some embodiments, the second metal reflective layer 211 may be a concavo-convex metal layer.

  The bottom substrate 214 may be made of glass. A transparent indium tin oxide (ITO) layer 212 may be provided as a pixel electrode on the inner surface of the bottom substrate 214 in the transmissive portion 201. A color filter not shown in FIG. 2 may be deposited on or near the surface of the upper substrate 224. The color filter may cover both the transmissive part 201 and the reflective part 202, or may only cover the transmissive part 101. The ITO layer 222 may be positioned as a common electrode between the upper substrate 224 and the liquid crystal layer 210. The bottom linear polarizer 216 and the top linear polarizer 226 may be mounted on the outer surfaces of the bottom substrate 214 and the top substrate 224, respectively.

  The light redirecting film 233 and the polarization recycling film 234 may be located between the BLU 236 and the bottom linear polarizer 216. The light redirecting film 233 is a tilted prism film and acts as a light directing tuning film to allow the incident light to enter the light redirecting film 233 or to reflect the incident light as shown in FIG. Can be directed in a substantially vertical upward direction. The light redirecting prism film 233 may cover both the transmissive part 201 and the reflective part 202 as a whole, or may alternatively include a pattern that covers only the reflective part 202. To show a clear example, the light redirecting film 233 is shown in FIG. 2 as having a symmetric reflective surface. In some embodiments, the reflective surface of the light redirecting film 233 may be configured to have an asymmetric reflective surface for redirecting incident light to the transmissive portion 201. For example, the reflection surface on the light redirecting film 233 further away from the transmission part 201 may have a smaller inclination than the reflection surface on the light redirecting film 233 near the transmission part 201.

  The polarization recycling film 234 reflects light in one polarization state, such as the first lateral polarization state, and transmits light in another polarization state, such as a second lateral polarization state orthogonal to the first lateral polarization state. It may function as a dual brightness enhancement film. The polarization recycling film 234 may include a plurality of layers therein. In certain embodiments, the dual brightness enhancement film may be a Vikuiti ™ DBEF film.

  In operation, in the reflector 202, the incident backlight 232a from the BLU 236 first passes through the light recirculation film 234 and the light redirecting film 233, and then enters the bottom linear polarizer 216 and in a particular linear polarization state. Enter the bottom area of the reflector 202. The incident backlight 232 a is incident on the first metal reflective layer 215. Similarly, the incident backlight 232b may be incident on the bottom surface of the second metal reflective layer 211. Incident backlights 232a and 232b are randomly reflected and pass through a bottom linear polarizer 216 having the same polarization state. Incident light 232a and 232b is recirculated and reflected by polarized recirculating film 234 and redirected by light redirecting film 233, or (1) coated with first metal reflective layer 215, or ( 2) Although not covered with the first metal reflective layer 215, it may be recirculated and redirected into the transmission part 201 from the region covered with the second metal reflective layer 211.

  Thus, the BLU light portion in the reflection unit 202 is recirculated in the transmission unit 201, and backlight recirculation is realized. Through the backlight recirculation described herein, more light is redirected from the reflective portion 202 into the transmissive portion 201. Therefore, a high light output efficiency from the BLU can be obtained, and an increased brightness in the transmission unit 201 can be achieved. Because more backlight is used more efficiently, power consumption from the BLU can be reduced, resulting in a transflective LCD with efficient power saving capabilities.

2.3 Circular Polarization FIG. 3 shows a schematic cross-sectional view of an exemplary transflective LCD unit structure 300. The LCD unit structure 300, which may include a pair of circular polarizers to transmit circularly polarized light, has a configuration for recirculating circularly polarized light. The circular polarizer may comprise a linear polarizer having a quarter wave plate or a linear polarizer having a half wave plate and a quarter wave plate to form a broadband circular polarizer. Also good.

  In some embodiments, the LCD unit structure 300 includes at least a transmissive part 301 and a reflective part 302. The liquid crystal layer 310 is located between the bottom base material 314 and the top base material 324. The transmission part 301 may have a liquid crystal cell gap different from the liquid crystal cell gap of the reflection part 302.

The overcoating layer 313 may be positioned in the reflective portion 302 in order to create a liquid crystal cell gap of the reflective portion that is smaller than the liquid crystal cell gap of the transmissive portion 301. In some embodiments, due in part to the overcoating layer 313, the liquid crystal cell gap of the reflective portion 302 may be about half of the liquid crystal cell gap of the transmissive portion 301. The material of the overcoating layer 313 may include acrylic resin, polyamide, or novolac epoxy resin. The overcoating layer 313 may be doped with inorganic particles such as silicon dioxide (SiO ₂ ) to provide scattering and diffractive optical properties. In some embodiments, the overcoating layer 313 may comprise an anisotropic liquid crystal material doped with a suitable dopant to perform a phase tuning function. In some other embodiments, the overcoating layer 313 may be a polymer liquid crystal material.

  The first metal reflective layer 315 may be located on the inner surface of the bottom substrate 314 in the reflector 302, which is the top surface of the bottom substrate 314 of FIG. The first metal reflective layer 315 can be prepared as a stretched gate metal or a separate reflective metal layer during the TFT process. The first metal reflective layer 315 may include an opaque reflective metal material such as Al or Ag, and may occupy all or a portion of the entire area of the reflective area 302. The inner surface, which is the upper surface of FIG. 3, of the overcoating layer 313 may be coated with a second metallic reflective layer 311 such as aluminum (Al) or silver (Ag) to serve as a reflective electrode. In some embodiments, the second metal reflective layer 311 may be an uneven metal layer.

  The bottom substrate 314 may be made of glass. A transparent indium tin oxide (ITO) layer 312 may be provided as a pixel electrode on the inner surface of the bottom base material 314 in the transmissive portion 301. Color filters not shown in FIG. 3 may be located on or near the surface of the upper substrate 324. The color filter may cover both the transmissive part 301 and the reflective part 302, or may only cover the transmissive part 301. The ITO layer 322 may further be positioned as a common electrode between the upper substrate 324 and the liquid crystal layer 310. The bottom linear polarizer 316 and the top linear polarizer 326 may be mounted on the outer surfaces of the bottom substrate 314 and the top substrate 324, respectively.

  A reflective polarizer 334 may also be added between the BLU 336 and the bottom circular polarizer 316. The reflective polarizer 334 may include a cholesteric liquid crystal film that acts as a circularly polarized reflector. The reflective polarizer 334 can reflect circularly polarized light in one rotational direction such as right-handed circularly polarized light and transmit circularly polarized light in the other rotational direction such as left-handed circularly polarized light. The reflective polarizer 334 may also include multiple layers that allow light recycling. In certain embodiments, the reflective polarizer 334 may be a CLC film commercially available from Merck.

  In operation, in the reflector 302, incident light 332a and incident light 332b from the BLU 336 first pass through the reflective polarizer 334 and then enter the bottom circular polarizer 316, for example in the left-handed circular polarization state of the reflector 302. Enter the bottom area. Incident light 332a and incident light 332b, which may be initially unpolarized from the BLU 336, pass through the bottom circular polarizer 316 and the corresponding light polarization state becomes a left-handed circularly polarized state.

  The incident light 332a and the incident light 332b in the left-handed circular polarization state then pass through the overcoating layer 313 having both the phase tuning function and the scattering function, and then are depolarized to become an elliptically polarized state. Incident light 332a and 332b are randomly reflected from the bottom surface of the first metal reflective layer 315 or the second metal reflective layer 311 and then become depolarized light or elliptically polarized light.

  Depolarized light or elliptically polarized light can be split into left-handed circularly polarized component light and right-handed circularly polarized component light. Therefore, when the depolarized light or elliptically polarized incident light 332a, 332b is reflected back to the bottom circular polarizer 316, the left-handed circularly polarized component light of the incident light 332a and incident light 332b is recirculated again. , Blocked from entering the bottom circular polarizer 316 and scattered back into the overcoating layer 313, while the right-handed circularly polarized component light of incident light 332 a and incident light 332 b passes through the bottom circular polarizer 316. pass.

  The component light that has been reflected by the reflective polarizer 334 and that has passed the right-handed circularly polarized state from incident light 332a and incident light 332b is recycled and (1) coated with a first metal reflective layer 315, Alternatively, (2) it is not covered with the first metal reflective layer 315 but is redirected into the transmission part 301 from the region covered with the second metal reflective layer 311.

  In this way, the BLU light portion in the reflection unit 302 is recirculated in the transmission unit 301, and backlight recirculation is realized. Through the backlight recirculation, more light is redirected from the reflector 302 into the transmissive part 301. It is not possible for a conventional transflective LCD to achieve this due to the rotational direction competition inherent in its circular polarizer configuration. Therefore, high light output efficiency from the BLU can be obtained, and increased brightness in the transmission unit 301 can be achieved. As more backlight is used more efficiently, power consumption from the BLU is reduced, resulting in a transflective LCD with efficient power saving capabilities.

2.4 Circular Polarization with Light Redirecting Film FIG. 4 shows a schematic cross-sectional view of an exemplary transflective LCD unit structure 400. The LCD unit structure 400, which may include a pair of circular polarizers to transmit circularly polarized light, has a configuration for recirculating circularly polarized light. The circular polarizer may comprise a linear polarizer having a quarter wave plate or a linear polarizer having a half wave plate and a quarter wave plate to form a broadband circular polarizer. Also good.

  In some embodiments, the LCD unit structure 400 includes at least a transmissive part 401 and a reflective part 402. The liquid crystal layer 410 is located between the bottom base material 414 and the top base material 424. The transmission part 401 may have a liquid crystal cell gap different from the liquid crystal cell gap of the reflection part 402.

The overcoating layer 413 may be positioned in the reflective portion 402 in order to create a liquid crystal cell gap of the reflective portion that is smaller than the liquid crystal cell gap of the transmissive portion 401. In some embodiments, due in part to the overcoating layer 413, the liquid crystal cell gap of the reflective portion 402 may be about half of the liquid crystal cell gap of the transmissive portion 401. The material of the overcoating layer 413 may include an acrylic resin, a polyamide, or a novolac epoxy resin. The overcoating layer 413 may be doped with inorganic particles such as silicon dioxide (SiO ₂ ) to provide scattering and diffractive optical properties. In some embodiments, the overcoating layer 413 may include an anisotropic liquid crystal material doped with a suitable dopant to perform a phase tuning function. In some other embodiments, the overcoating layer 413 may include a polymer liquid crystal material.

  The first metal reflective layer 415 may be located on the inner surface of the bottom substrate 414 in the reflector 402, which is the top surface of the bottom substrate 414 in FIG. The first metal reflective layer 415 can be prepared as a stretched gate metal or a separate reflective metal layer during the TFT process. The first metallic reflective layer 415 may include an opaque reflective metallic material such as Al or Ag, and may occupy a portion or all of the entire area of the reflective area 402. The inner surface, which is the upper surface of FIG. 4, of the overcoating layer 413 may be coated with a second metallic reflective layer 411 such as aluminum (Al) or silver (Ag) to serve as a reflective electrode. In some embodiments, the second metal reflective layer 411 may be an uneven metal layer.

  The bottom substrate 414 may be made of glass. A transparent indium tin oxide (ITO) layer 412 may include a pixel electrode on the inner surface of the bottom substrate 414 in the transmissive portion 401. Color filters not shown in FIG. 4 may be located on or near the surface of the upper substrate 424. The color filter may cover both the transmissive part 401 and the reflective part 402, or may only cover the transmissive part 401. The ITO layer 422 may be positioned as a common electrode between the upper base material 424 and the liquid crystal layer 410. The bottom circular polarizer 416 and the top circular polarizer 426 may be mounted on the outer surfaces of the bottom substrate 414 and the top substrate 424, respectively.

  The light redirecting film 433 and the reflective polarizer 434 may be located between the BLU 436 and the bottom circular polarizer 416. The light redirecting film 433 is a tilted prism film, which acts as a light directing tuning film, after the incident light enters or is reflected from the light redirecting film 433, the incident light is reflected in the desired direction of FIG. Can be directed in a substantially vertical upward direction. The light redirecting prism film 433 may cover both the transmissive part 401 and the reflective part 402 as a whole, or may alternatively include a pattern that covers only the reflective part 402. To show a clear example, the light redirecting film 433 is shown in FIG. 4 as having a symmetrical reflective surface. In some embodiments, the reflective surface of the light redirecting film 433 may be configured to have an asymmetric reflective surface for redirecting incident light to the transmissive portion 401. For example, the reflection surface on the light redirecting film 433 further away from the transmission part 401 may have a smaller inclination than the reflection surface on the light redirecting film 433 near the transmission part 401.

  The reflective polarizer 434 may include a cholesteric liquid crystal film that acts as a circularly polarized reflector. The reflective polarizer 434 can reflect circularly polarized light in one rotation direction such as right-handed circularly polarized light and transmit circularly polarized light in the other rotational direction such as left-handed circularly polarized light. The reflective polarizer 434 may also include multiple layers that allow light recycling. In certain embodiments, the reflective polarizer 434 may be a CLC film from Merck.

  In operation, in the reflector 402, incident light 432a and incident light 432b from the BLU 436 first pass through the reflective polarizer 434 and the light redirecting film 433, and then enter the bottom circular polarizer 416, for example, left-handed circularly polarized light. In the state, it enters the bottom region of the reflection portion 402. Incident light 432a and incident light 432b, which may be initially unpolarized from the BLU 436, pass through the bottom circular polarizer 416 and the corresponding light polarization state becomes a left-handed circularly polarized state.

  The incident light 432a and the incident light 432b in the left-handed circular polarization state then pass through the overcoating layer 413 having both the phase tuning function and the scattering function, and then are depolarized to become an elliptical polarization state. The incident lights 432a and 432b are randomly reflected from the bottom surface of the first metal reflection layer 415 or the second metal reflection layer 411 and then become depolarized light or elliptically polarized light. This depolarized light or elliptically polarized light can be split into left-handed circularly polarized component light and right-handed circularly polarized component light. Therefore, when the depolarized light or elliptically polarized incident light 432a, 432b is reflected back to the bottom circular polarizer 416, the left-handed circularly polarized component light of the incident light 432a and incident light 432b is recycled again. , Blocked from entering the bottom circular polarizer 416 and scattered back into the overcoating layer 413, while the right-handed circularly polarized component light of incident light 332 a and incident light 332 b passes through the bottom circular polarizer 416. pass.

  The component light reflected and redirected by the reflective polarizer 434 and the light redirecting film 433 and having a right-handed circular polarization state from the incident light 432a and the incident light 432b is recirculated, and (1) the first (2) Although not covered with the first metal reflective layer 415, it may be redirected into the transmissive part 401 from the region covered with the second metal reflective layer 411. Good.

  Thus, the BLU light portion in the reflection unit 402 is recirculated in the transmission unit 401, and backlight recirculation is realized. As described herein, more light is redirected from the reflector 402 into the transmitter 401 through backlight recirculation. It is not possible for a conventional transflective LCD to achieve this due to the rotational direction competition inherent in its circular polarizer configuration. Therefore, high light output efficiency from the BLU can be obtained, and increased brightness in the transmission unit 401 can be achieved. As more backlight is used more efficiently, power consumption from the BLU is reduced, resulting in a transflective LCD with efficient power saving capabilities.

3. Extensions and Variations To show a clear example, the transflective LCD unit structure described herein comprises a first metallic reflective layer and a second metallic reflective layer. The transflective LCD unit structure may further include a third reflective layer between the first base material layer and the second base material layer. The third reflective layer may be disposed on the transmissive part, the reflective part, or both of the transflective LCD. In some embodiments, the first metal reflective layer may be a pattern comprising a plurality of reflective components.

  In order to show a clear example, the first electrode layer and the second electrode layer may be respectively disposed adjacent to the first base material layer and the second base material layer. In other embodiments, both electrode layers may be placed adjacent to one of the first substrate layer and the second substrate layer.

  While the preferred embodiments of the invention have been illustrated and described, it will be clear that the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions and equivalents will become apparent to those skilled in the art without departing from the spirit and scope of the invention as set forth in the appended claims.

Claims (33)

In a transflective liquid crystal display comprising a plurality of pixels, each pixel is
A first polarizing layer;
A second polarizing layer;
The first base layer and the second base layer facing the first base layer, wherein the first base is between the first polarizing layer and the second polarizing layer. A material layer and the second base material layer;
A liquid crystal material between the first substrate layer and the second substrate layer;
An overcoating layer adjacent to the first substrate layer, the overcoating layer comprising at least one opening that partially forms a transmissive portion, the remainder of the overcoating layer partially comprising a reflective portion; The overcoating layer,
A first reflective layer adjacent to the first base material layer, the first reflective layer covering at least a part of the reflective portion;
A second reflective layer between the overcoating layer and the second substrate layer, the second reflective layer substantially covering the reflective portion;
With
The transflective liquid crystal display, wherein the first reflective layer is between the second reflective layer and the first base material layer.   The transflective liquid crystal display according to claim 1, wherein the first polarizing layer and the second polarizing layer are linear polarizers.   The transflective liquid crystal display according to claim 1, wherein the first polarizing layer and the second polarizing layer are circular polarizers.   The transflective liquid crystal display according to claim 1, wherein the overcoating layer is a scattering and diffractive overcoating layer.   The transflective liquid crystal display according to claim 1, wherein the overcoating layer is a phase tuning film.   A light source for directing light through the at least one aperture in the overcoating layer, wherein the first polarizing layer is adjacent to an outer surface of the first substrate layer, and the pixel includes the light source and the light source; The transflective liquid crystal display according to claim 1, further comprising a polarization recycling film between the first polarizing layer and the first polarizing layer.   The transflective liquid crystal display according to claim 6, wherein the pixel includes a light redirecting film between the light source and the first polarizing layer.   8. The transflective liquid crystal display according to claim 7, wherein the light redirecting film covers both a part of the transmission part and a part of the reflection part.   8. The transflective liquid crystal display according to claim 7, wherein the light redirecting film covers only the area of the reflecting portion.   The transflective liquid crystal display according to claim 1, further comprising a first electrode layer adjacent to the first base material layer.   The transflective liquid crystal display according to claim 9, wherein the first electrode layer is an oxide layer.   The transflective liquid crystal display according to claim 1, wherein the pixel includes a switching element configured to determine a light transmission intensity passing through the transmission part.   The transflective liquid crystal display according to claim 12, wherein the switching element further comprises a transistor-transistor logic interface.   The transflective liquid crystal display according to claim 1, wherein the transmissive portion is covered with a color filter.   The pixel further includes a third reflective layer between the first base material layer and the second base material layer, and the third reflective layer covers a part of the area of the pixel. The transflective liquid crystal display according to claim 1, wherein the liquid crystal display is a transflective liquid crystal display. In the computer,
One or more processors;
A transflective liquid crystal display coupled to the one or more processors and comprising a plurality of pixels;
The pixel is
A first polarizing layer;
A second polarizing layer;
The first base layer and the second base layer facing the first base layer, wherein the first base is between the first polarizing layer and the second polarizing layer. A material layer and the second base material layer;
A liquid crystal material between the first substrate layer and the second substrate layer;
An overcoating layer adjacent to the first substrate layer, the overcoating layer comprising at least one opening that partially forms a transmissive portion, the remainder of the overcoating layer partially comprising a reflective portion; The overcoating layer,
A first reflective layer adjacent to the first base material layer, the first reflective layer covering at least a part of the reflective portion;
A second reflective layer between the overcoating layer and the second substrate layer, the second reflective layer substantially covering the reflective portion;
With
The computer according to claim 1, wherein the first reflective layer is between the second reflective layer and the first base material layer.   The computer according to claim 16, wherein the first polarizing layer and the second polarizing layer are linear polarizers.   The computer according to claim 16, wherein the first polarizing layer and the second polarizing layer are circular polarizers.   The computer of claim 16, wherein the overcoating layer is a scattering and diffractive overcoating layer.   The computer according to claim 16, wherein the overcoating layer is a phase tuning film.   A light source for directing light through the at least one aperture in the overcoating layer, wherein the first polarizing layer is adjacent to an outer surface of the first substrate layer, and the pixel includes the light source and the light source; The computer according to claim 16, further comprising a polarization recycling film between the first polarizing layer and the first polarizing layer.   The computer of claim 21, wherein the pixel comprises a light redirecting film between the light source and the first polarizing layer.   The computer of claim 16, wherein the pixel comprises a switching element configured to determine a light transmission intensity through the transmission.   The pixel further includes a third reflective layer between the first base material layer and the second base material layer, and the third reflective layer covers a part of the area of the pixel. The computer according to claim 16, characterized in that: In a method of manufacturing a transflective liquid crystal display,
Providing a plurality of pixels, the pixels comprising:
A first polarizing layer;
A second polarizing layer;
The first base layer and the second base layer facing the first base layer, wherein the first base is between the first polarizing layer and the second polarizing layer. A material layer and the second base material layer;
A liquid crystal material between the first substrate layer and the second substrate layer;
An overcoating layer adjacent to the first substrate layer, the overcoating layer comprising at least one opening that partially forms a transmissive portion, the remainder of the overcoating layer partially comprising a reflective portion; The overcoating layer being formed
A first reflective layer adjacent to the first base material layer, the first reflective layer covering at least a part of the reflective portion;
A second reflective layer between the overcoating layer and the second substrate layer, the second reflective layer substantially covering the reflective portion;
With
The method of claim 1, wherein the first reflective layer is between the second reflective layer and the first substrate layer.   26. The method of claim 25, wherein the first polarizing layer and the second polarizing layer are linear polarizers.   26. The method of claim 25, wherein the first polarizing layer and the second polarizing layer are circular polarizers.   The method of claim 25, wherein the overcoating layer is of the scattering and diffractive type.   The method of claim 25, wherein the overcoating layer is a film having a phase tuning function.   Providing a light source, the light source providing light through the at least one aperture in the overcoating layer, the first polarizing layer being adjacent to an outer surface of the first substrate layer; 26. The method of claim 25, wherein the pixel comprises a polarization recycling film between the light source and the first polarizing layer.   The method of claim 30, wherein the pixel comprises a light redirecting film between the light source and the first polarizing layer.   The method of claim 25, wherein the pixel comprises a switching element configured to determine a light transmission intensity through the transmission.   The pixel further includes a third reflective layer between the first base material layer and the second base material layer, and the third reflective layer covers a part of the area of the pixel. 26. The method of claim 25, characterized in that

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